In image display devices such as a cathode-ray tube display device (CRT), a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), and a field emission display (FED), an optical layered body composed of functional layers having various performances such as a reflection prevention performance, an antistatic performance, a hard coating property, and a stain prevention property is formed.
Such an optical layered body is obtained by layering various functional layers on a light-transmitting substrate. Accordingly, in the case where a hard coat, for example, is formed on a light-transmitting substrate, uneven patterns called interference fringes appear due to the interference of the reflected light on the interface of the light-transmitting substrate and the hard coat layer and the reflected light on the hard coat surface and unevenness of the coating thickness to result in a problem that the appearance is deteriorated.
In order to prevent generation of the interference fringes, for example, in the case where a hard coat layer is formed on a light-transmitting substrate, it has been know to use a solvent which can penetrate the light-transmitting substrate to swell or dissolve the substrate for a resin composition for forming the hard coat layer (e.g., see Patent Literatures 1 and 2). Use of a resin composition containing such a solvent forms an impregnated layer by impregnating the light-transmitting substrate with the resin in the resin composition owing to the penetration of the solvent to the light-transmitting substrate, and as a result, the interface between the light-transmitting substrate and the hard coat layer can substantially be eliminated to prevent generation of the interference fringes.
However, in the case of a conventional optical layered body in which interference fringes are prevented by forming such an impregnated layer, it is required to make the impregnated layer thick for sufficiently preventing generation of interference fringes, and thus it is inevitably needed to increase the application amount of a composition to be used at the time of forming a hard coat layer.
Accordingly, it results in a problem that an optical layered body may become difficult to be made thin and may be curled, and if the application amount of the composition at the time of forming a hard coat layer formation is large, it also results in a problem that the thickness of the hard coat layer to be formed becomes uneven and the production cost becomes high.
As an optical layered body to be used for the surface of an image display device, an optical layered body (an antiglare film) is also known which is provided with an antiglare property by forming an antiglare layer having, on its surface, an uneven form on a light-transmitting substrate. However, although preventing generation of interference fringes, the antiglare film causes a problem of giving white muddiness and lowering the contrast.